Mineral detector and rectifier for radioreception



June 16,1925. l l t J. MMENAM|N INERL BECTR ANDCTIFIER FOR' RDI'RICETION y '5vr shuts-Sheet 1 Filed Oct. 17, 1922 aow?. M

June 16,1925. Y y

'.J. MQMENAMIN MINERAL Daumen :um nnornmn ron nxmoxncsr'rrox Fi1eaont. 17,1922 s sheets-sheet 2 June 16. |925'. 1,542,258

- 1- J. MGMENAMIN MINERAL DETECTOR Aun lmc'rnrz Formfeacsprion med oct. 1v, 1922 :shuts-she@ s Patented June 16, 1925.

`UNITED STATES PATENT osier..

JOSEPH MCMEN'AMIN, OF PHILADELPHIA, PENNSYLVANIA.

MINERAL DETECTOR yann RECTIEIEE. non nAnIoE-EoEETroNL Application led October 17,1922. Serial No` 595,025.

length, the currents are carriedby lead-in wire to the receiving apparatus which consists of a tuning device, a rectifying device and a pair of head phones. The high frequency alternating currents are inaudible in the head-phones which, at such high frequency, are .sensitive to direct current only. This zcalls for the use of a rectifying device which will transform the high frequency alternating currents into high fre quency directcurrents. The rectifying device generally used is known as the mineral or crystal `cat-Whisker detector, the basic feature of which is mineral, such as galena or silicon which has the property of transforming alternating currents into rdirect currents. The entire surfaces of these minerals do not possess the-serectifying quali` ties or-do not possess them in equal degree. For this reason the cat Whisker, a longthin wire is used to explore the surface of the mineral to detect th-e sensitive spots. The device is most eliicient when the catwhisker presses very lightly upon a sensitive spot in thev mineral and the delicate adjustment requiredV renders the device eX- tremely sensitive to body vibration, the slightest jar being sufficient to throw the detector out of adjustment and the instrument out of commission. lnasinuch as under ordinary conditions of use, and especially on ships, railway trains or other traveling objects, the rectifying device 'is subject to frequent jars, it is frequently out of commission. f

My invention relates to the general type of detector andv rectifier described above and has its object to provide aninstrument of simple, compact and durable construction which will permit practically instantaneous adjustment without `requiring skill on the part of the operator and which, once adjusted, maintains its position regardless of vibration or jarring of the instrument or its supports. j

rlliis object, and other advantageous ends which will be described hereinafter, I attain in the following Vmanner, reference being had to the accompanying drawings in whi cli- Figure l is a top plan view of any instrument embodying my invention,

Figure 2 is an enlarged vertical section on line 2 2 of Figure l,

Figure 3 is a horizontal section on line 33 of Figure 2,

Figure 4t a horizontal section on line %l of Figure 2, and

Figure 5 a bottom plan view `of the .switching knob and its lining.

The vital factor in the invention is a plurality of insulated electric conducting wires compactly grouped at one end with their grouped ends flush with `each other and adapted to be engaged by the Hush face of a mass of rectifying mineral thereby presenting a plurality of points of contact with the mineral, the other ends of the wires being disposed for contact Ywith a detecting linger.

. In the drawings l designates the wires, shown as fifty in number. At one end these wires are assembled in a tube 2 with their ends flush and adapted to be engaged by a flush face of a mass of rectifying material 8 which may be galena, silicon or any mineralof like properties. The other ends are looped about an insulating ring 4, as iiidi- K cated at 5, and so disposed as to be selectively engaged by a detecting finger. The aggregation of insulated wires in tube 2 forms what is, in effect, a section of cable and for convenience it will hereinafter be referred tok as the multi-point cable. The working parts of the instrument are enclosed by a metallic ybase plate 7, an annular rotatable, dial-carrying member 8, hereinafter called. the switching knob, having its top closed eX- cept fora circular central opening 9 adapted to receive a metallic mineral adjuster 10.

The mineral adjuster is in the form of an in- 'Mverted cup having in its top a central convex depression forming a boss l1, and having the inner wallrof its depending flange l2 threaded to take over the threaded outer wall of ythe depending` 'i'ange 14 of a mineral holder 13 which is also in the form of an inverted cup. The mineral holder has a lresilient top lGO adapted to be engaged and depressed by boss 11, and carries a mineral cup 15, in which the mineral is housed. The mineral cup is also an inverted cup and is 'secured'to the top ot' the mineral holderconcentrically. The lower and exposed surface of the mineral is flush with Vits housing and adapted to engage the flush top ot the multi-point cable. Tube 2, which is of insulating material, is seated in the central opening ot a metallic ring 1G, hereinafter called the securing ring. This ring has a wall ot' substantialthickness, in which there is a downwardly extending annular recess 17 having its inner wall threaded to receive a thread on the inner wall of flange 111 of the mineral holder. The recess also houses the lower part of the depending flange 12 of the mineral adjuster. The wires 1, leading from the multi-point cable to the insulating ring et are insulated from the base plate 7 by an insulating cup ,18 and from the securing ring 16 by an insulating cup 19. Theswitching knob 8 has a metallic lining 2O out of which is pressed the detecting inger 6 and a tongue '21 adapted to engage in'a `groove 22 in the base plate and hold the dial plate in engagement therewith. An 'insulating ring `surrounds the upper V.part of securing rin'g l1G and is 'surrounded by a metallic 'ring 24; which contacts withthe metallic li'ningkQQ and serves as an vupper bearing for the switching knob. Base VAplate 7 'is provided with an annular shoulder 25 `whicli contacts -with lining 20 and rserves as a lower bearing for the switching 'lniob and to make electrical connection with rIhe 'metallic :base is mounted upon a panel-"26 of 'insulating material and secured "thereto by inea-ns ofsere'ws 27, 28 and 29.

Sciew'' talles into'the base and serves as a binding screw Ato mal-*ge electrical connection through the base tothefdeteeting finger 6. vScrew 28 'takes through, but is insulated froinythe base and into securing ring` 16 and `serves #as 'a binding screw vto make electrical connection with thesecurin'g ring and ininreral cup. v Screw '29 takes through the base -into securing ring 1G, is insulated from the base, and serves only as securing means. Pan'el'26 'is provided Vwith an indicating mark 3G, shown asan arrow, and primarily registering with 'the Zero marl; of the dial.

All metallic partsare preferably of brass.

vrrlhe electrical circuit vthrouglrthe instrument `.is from binding screw27, base plate 7, shoulder 25, detecting finger 6, one of the wires which contacts with'the mineral, the 'mineral cup 15, ymineral holder v13 and cylinder v16 to binding sc'r'eiv '28.

. For operation, the-parts being assembled asshown in Figure 2, and in circuit, but with the mineral slightly out of Contact with theimulti-point cable, mineral'adjuster 10 is screwed down over mineralholder 13 causing boss 11 to exert pressure upon the resilient top oi the mineral holder, the turning of the adjuster being continued until the flush 'tace of the mineral is brought into contact withthe flush face oia the multi-point cable, this operation bringing a number of the cable wires into contact with as many sensitive spots on the mineral. Switching knob S is then rotated until detecting linger 6 comes into Contact with one of the cable wires leading to a sensitive spot on the mineral. rEhe mineral adjuster' is then turned back and forth' until the signals come in strongest thus indicating the most sensitive adjustment. This adjustment of the inineralI relatively to the inulti-point cable 'may be taken as a permanent adjustment. By revolving the switcl'iing knob a number of sensitive contacts, but varying in sensitiveness, will be found from which the most seiisitive may be selected. Vilhen the most sensitive point has once been determined, this adjustment is also permanent but, il 'for any reason, the switching knob should be turned, the 'adjustment may be restored 'by turning the knob to its former position as indicated by the dial. e

llhen the proper contact of the minera with the opposing face of the cable is once obtained, 'the contact is permanently held and the detecting finger is also positively vheld in cont-act with the wire so that the efficiency of the instrument is 'not affected by, vibration.

While I have described my invention as taking a particular form, it will be understood that the various parts of my invention maybe changed without-departing from the spirit thereof, and'hence I do not limit myself to the precise construction set forth, but consider -that I am at liberty to make such changcs'and alterations as fairly come within the scope'ot the appended claims.

Having thus described my invention, what vI claim as new and desire 'to secure by Letters 'Patent is 1. A rectifier and detector i''or radio reception comprising a mass of rectiiiying material, a pluralityoi insulated wires grouped at one end to form a compact mass with a flush tace and presenting a plurality of fixed contacts opposed to the mineral, and means for selectively bringing any ot' the wires into circuit.

2. A rectifier anddetector for radio reception comprising a mass of rectiifying rmaterial having a flush face; yan insulating tube; aV plurality oft-insulated wires grouped at one end into a compact'ma'ss, immediately enclosed by the insulating tube and presenting a flushed face opposed yto the. flush face of "the mineral, and means for selectively bringing any of the wires into circuit.

3. A rectifier and detector-for radio reception comprising a mass of rectifying mineral having a iiush `face; a plurality of insulated wires grouped at one end to form a compact mass and presenting a fixed flush face opposed tothe flush face of the mineral, means for selectively bringing any of the wires into circuit, and means for adjusting the mineral relatively to the grouped ends of the wires.

4L. A rectifier and detector for radio reception comprising an insulating ring; a pluiality of insulated wires grouped at oneend and presenting a fixed flush face, the other ends of the wires being connectedy with the insulating ring; a mass of mineral having a liush face opposed to the flush face of the wires; a rotatable switching knob of insulating material embracing the insulating ring, and a metallic detecting finger carried by the knob and adapted to make electric contact with the ends of the wires connected with the insulating ring.

5. A rectifier and detector for radio reception comprising an insulating ring; a

plurality of insulated wires grouped at oneV end and presenting a fixed `iiush face, the other ends of the wires being connected with the insulating ring; a mass of mineral having a flush face opposed to the flush face of the wires; a rotatable switching knob of insulating material embracing the insulating ring, and having a metallic lining, and a detecting finger projecting from the lining, adapted to make electric contact with the ends of the wires connected with the insulating ring.

6. A rectifier and detector for radio reception comprising an insulating ring; a plurality of insulated wires, grouped at one end and presenting a flush face, the other endsV of the wires being looped over the insulating ring; a mass of mineral having a flush face opposed to the flush face of the wires; a rotatable switching knob of insulating inaterial embracing the insulating ring, and a metallic detecting finger carried by theknob and adapted to engage the looped ends of the wires.

'Z'. A rectifier and detector fory radio reception comprising an insulating ring; a plurality of insulated Wires, grouped at one end and presenting a flush face, the other ends of the wires being looped over the insulating ring; a mass of mineral having a fiush face opposed to the flush face ofthe wires; a rotatable switching knob ofinsulating material embracing the insulating ring, and having a metallic lining, and a detecting linger projecting from the lining and adapted to engage the looped ends of the wires.`

8. A rectifier anddetector for radio reception comprising a mineral holder having a resilient top; a mineral cup secured to the resilient top; a mass of rectifying mineral secured in the cup; a plurality of wires grouped at one end, the grouped ends being opposed to the mineral; a switching linger tube within the ring 5' disposed for contact with the other ends of vthe wires, and a mineral adjuster adapted to` engage with the resilient top of the mineral holder.

9. A rectiiier and detector for radio reception comprising a mineral holder having a dependingannular flange kthreaded inter* ally and externally; a kmetallic securing ring having' a depending recess with its inner wall threaded to receive the internal thread of the mineral holder; an insulating a plurality of wires having one or" their ends grouped within the tube, and a switching linger disposed for contact rwith the 'other ends of the wires.

l0. A rectifier and detector for radio reception comprising a mineral holder having a depending annular iange threaded internally and externally; a metallic securing ring having a depending recess with its in-` ner wall threaded to receive the internal thread of the mineral holder; a mineral adjuster having a depending annular flange threaded internally and adapted to engage' the threaded external flange of the mineral holder; an insulating tube within the ring; a plurality of' wires having one of their ends grouped within the tube, and a switching finger disposed for contact with the other ends of the wires.

l1. A rectifier and detector for radio yreception comprising a mineral holder having a depending annular flange threaded inter` nally and externally; a metallic securing ring having a depending recess with its inner wall threaded to receive the internal thread of the mineral holder; an insulating tube within the ring; an insulating ring; a

Eil

plurality of wires having one of their ends grouped within the insulating tube and their other ends looped about the insulating ring, and a switching finger disposed for contact with the looped ends.

12. A rectifier and detector for radio reception comprising a metallic base plate;r 33- a metallic securing ring attached thereto but insulated therefrom; a mineral holder and a mineral' adjuster carried by the securing ring; an insulating ring; a plurality of insulated wires having one ot their ends grouped within the securing ring and opposed to the mineral and their other ends looped over the insulating ring; arotatable switching knob; switching means carried thereby adapted to selectively bring the wires into circuit, and means for holding the switching knob in engagement with the base plate.

13. A rectifier and detector for radio reception comprising a metallic base plate; a metallic securing ring attached thereto but insulated therefrom; a mineral holder and a mineral adjuster carried by the' securing ring; an insulating ring; a plurality of insulated wires having one of their ends grouped `Within the securing ring and opposed to the mineral and their other ends looped over the insulating ring-5 an `insulating cup between the base plate and 'the wires; an insulatingcup between the Wires and the securing ring; a rotatable switching knob; switching means carried thereby adapted to selectively bring the Wires into circuit, and means for holding the switching knob in engagement With the base plate.

M. A rectiiier and detector for radio reception comprising a metallic base plate; a metallic securing` ring attached thereto but insulated therefrom; a inineral holder and a mineral adjuster carried by the securing ring; 'an insulating ring; a plurality of insulated YWires having one of their ends rouped Within the securing ring and the 'other ends loop'edoyer the insulating ring;

la rotatable switching knob having4 a 'ine- "t'allicdiiiing lan insulating ring disposed naine 'to this vspecification in the presence of trio subscribing Witnesses.

JOSEPH MCMENAMIN.

lVitnesses Grenen B. PAnKiNsoN, Cuirs. E. Porre. 

